The present invention generally relates to an apparatus for producing ends or shells for can-type containers such as beverage containers or the like and, more particularly, to a forming apparatus for curling a periphery of the shells.
Individual components of a two-part beverage container typically include a unitary deep drawn cup or body which terminates in an outwardly extending curl and an end or shell which has a peripheral inwardly extending curl. The body and shell curls are connected in a seaming operation to attach the shell to the body with a hermetic seal. The shell is typically provided with a self-opening structure such as a tear tab and related score lines to provide access to the contents of the container. The components are typically manufactured from a suitable metal such as, for example, aluminum or steel.
The shell is conventionally produced by a two step process: (1) punching and forming a strip of sheet metal into a shell using a press; and (2) curling an outer periphery of the shell using a forming or curling apparatus. The curling apparatus often consists of a rotating wheel having an inner ring or die and a stationary base having a plurality of outer ring-segments or dies. Typically, four to six outer ring-segments are provided to collectively extend about 240 degrees. The inner ring has an inner groove and the outer ring-segments together form an outer groove for forming curls on the periphery of the shells. As the wheel rotates, the shells pass between the inner and outer grooves. The distance between the inner and outer grooves gradually narrows so that the curls are formed as the shells pass therebetween. The groove formed by the outer ring-segments is typically eccentric to the rotational axis of the wheel so that the shells rotate as they pass between the inner and outer grooves. To increase production of the curling apparatus, the inner rings and outer ring-segments are often stacked to form a plurality of levels.
U.S. Pat. Nos. 5,491,995 and 5,669,259 to Stodd disclose a curling apparatus for high speed production of shells for beverage containers, the disclosures of which are expressly incorporated herein in their entirety by reference. The curling apparatus utilizes six outer ring-segments which are positioned opposite each inner ring. A series of peripherally spaced adjustment screws project radially inward through a flange to engage the ring-segments for precisely adjusting the radial position of each ring-segment. The ring-segments are precisely positioned using the adjustment screws to obtain the desired eccentricity of the outer groove formed by the ring segments and the desired narrowing of the distance between the inner and outer grooves. Each level of outer ring-segments is bolted directly to the level directly below.
While such a curling apparatus may suitably curl the shells during operation, it has numerous shortcomings with regard to set-up and tear-down requirements. Adjusting the position of each of the outer ring-segments to obtain the desired eccentricity and diameter is very time consuming. This problem is further exacerbated when multiple levels are utilized because each level is built onto, that is bolted to, the preceding level. To adjust a level, each of the levels located above that level must be removed. It is common for production to be stopped a week for set-up of about eight sets of ring-segments. This is particularly a problem because the grooves must be cleaned regularly to remove debris such as, for example anodizing and the ring-segments of upper levels must be removed to access all of the grooves. Accordingly, there is a need in the art for an improved curling apparatus which requires reduced tear-down and set-up time compared to prior art systems and/or permits adjustment to each level without disassembly of the other levels.
The present invention provides a curling apparatus which overcomes at least some of the above-noted problems of the related art. According to the present invention, a die for curling outer peripheries of container shells includes a unitary ring segment having an inner surface. The ring segment has a length extending in the range of about 120 degrees to about 300 degrees. A groove is provided in the inner surface and extends the length of the ring segment. The groove sized and shaped to form the container shells. According to a preferred embodiment, the unitary ring segment has a length extending about 240 degrees. By utilizing a unitary ring segment according to the present invention, set-up time of a curling apparatus is substantially reduced because the position of only a single ring-segments needs to be adjusted.
According to another aspect of the present invention, a die for curling outer peripheries of container shells includes a unitary ring segment having an inner surface and a groove provided in the inner surface and extending the length of the ring segment. The groove is sized and shaped to form the shells and the groove is eccentric. By utilizing a unitary ring segment with eccentricity built-in according to the present invention, set-up time of a curling apparatus is substantially reduced because multiple ring segments do not have to be adjusted to obtain eccentricity.
According to yet another aspect of the present invention, a curling apparatus for curling outer peripheries of container shells includes an inner ring having an outer surface and a groove in the outer surface and an outer ring-segment having an inner surface and a groove in the inner surface. The inner ring groove extends the entire periphery of the inner ring. The outer ring-segment groove extending the length of the outer ring-segment. The outer ring-segment partially encircles the inner ring with the inner ring groove facing the outer ring-segment groove. The curling apparatus also includes an adjustment device adapted to selectively move the outer ring segment relative to the inner ring to adjust a distance between the inner ring groove and the outer ring-segment groove at a desired location along the outer ring-segment groove. The adjustment device includes a rotatable cam member. In a preferred embodiment, the cam member is rotatable about a vertical axis and is located in a vertically extending opening in the outer ring segment. By utilizing an adjustment device according to the present invention, the position of the outer ring-segment can be easily and precisely adjusted from a desired location.
According to even yet another aspect of the present invention, a curling apparatus for curling outer peripheries of container shells includes a plurality of inner rings vertically stacked and a plurality of outer ring-segments vertically stacked. Each of the inner rings have an outer surface and a groove in the outer surface. Each inner ring groove extends an entire periphery of the inner ring. Each of the outer ring-segments has an inner surface and a groove in the inner surface. Each outer ring-segment groove extends the length of the outer ring-segment. The outer ring-segments partially encircle the inner rings with the inner ring grooves facing the outer ring-segment grooves. The curling apparatus also includes plurality of adjustment devices adapted to selectively move the outer ring segments relative to the inner rings to adjust a distance between the inner ring groove and the outer ring-segment groove at a desired location along the outer ring-segment groove. Each outer ring-segment has one of the adjustment devices associated therewith. Each adjustment device includes a cam member rotatable about a vertical access and located within vertically extending openings in the outer ring-segments. Preferably, one of the openings associated with the cam member is in an associated outer ring-segment and is engaged by the cam member and the remaining openings associated with the cam member are clearance openings. The outer ring-segments are preferably secured with common mounting fasteners which extend through clearance openings in each of the outer ring-segments. By utilizing a an adjustment device according to the present invention, the position of any of the outer ring-segments can be easily and precisely adjusted from a desired location without removal of any of the other outer ring segments.
From the foregoing disclosure and the following more detailed description of various preferred embodiments it will be apparent to those skilled in the art that the present invention provides a significant advance in the technology and art of apparatus for curling container shells. Particularly significant in this regard is the potential the invention affords for providing an easy-to-use, high quality, feature-rich, low cost system. Additional features and advantages of various preferred embodiments will be better understood in view of the detailed description provided below.